Sorting array of objects by properties (multi-level)

Question

I have an array of objects that is like this:

var array = [
    {minutes: 45, hours: 4, meridiem: "PM"},
    {minutes: 00, hours: 8, meridiem: "AM"},
    {minutes: 45, hours: 8, meridiem: "AM"},
    {minutes: 30, hours: 3, meridiem: "PM"},
    {minutes: 15, hours: 11, meridiem: "AM"},
    {minutes: 00, hours: 1, meridiem: "PM"}
]

Essentially I need to sort by time, earliest first. So by AM/PM then by hours and then by minutes if hours and meridiem are equal.

Here is what I've tried

this.currentTours.sort(function(a,b) {
  if (a.meridiem != b.meridiem) {
    return 1
  }
  if ((a.dateR.meridiem == b.dateR.meridiem) && a.dateR.hours != 
  b.dateR.hours) {
    return 1
  }
  if (((a.dateR.meridiem == b.dateR.meridiem) && a.dateR.hours != 
  b.dateR.hours) && a.dateR.minutes != b.dateR.minutes) {
    return 1
  }
  return a.dateR.meridiem - b.dateR.meridiem
})

Getting past 1 layer of properties is where I get stuck.

Show us what you already tried so we can help you to handle it. This is not a site where people do your work for you. — voloshin
– voloshin, Commented Sep 14, 2017 at 17:48
I think this -- How do you sort an array of objects based on multiple properties -- is a really good question, but it's unfortunate that time is the example in use. It begs the question, as Nina says, why not just a 24 hour integer? {minutes: 45, hours: 4, meridiem: "PM"} is 1645 while {minutes: 17, hours: 9, meridiem: "AM"} is 945. Sorting that is trivial. An example with, say, {name:"Fred", age:27, country:"GBR"} where you want to sort by Country, then Age, then Name doesn't raise "Why don't you just X?" questions. — Stephen P
– Stephen P, Commented Sep 14, 2017 at 21:21
I think using a 24hr system is a good recommendation. Thanks. — slotdp02
– slotdp02, Commented Sep 14, 2017 at 21:37

Nina Scholz · Accepted Answer · 2017-09-14 18:26:18Z

3

You could use a chained approach for a nested sorting, with a hour correction for 12 am or pm. These values are interpreted as zero.

(a.hours < 12) * a.hours

var array = [{ minutes: 45, hours: 4, meridiem: "PM" }, { minutes: 00, hours: 8, meridiem: "AM" }, { minutes: 45, hours: 8, meridiem: "AM" }, { minutes: 30, hours: 3, meridiem: "PM" }, { minutes: 15, hours: 11, meridiem: "AM" }, { minutes: 00, hours: 1, meridiem: "PM" }, { minutes: 00, hours: 12, meridiem: "PM" },{ minutes: 00, hours: 12, meridiem: "AM" }];

array.sort(function (a, b) {
    return (b.meridiem === 'AM') - (a.meridiem === 'AM')
        || (a.hours < 12) * a.hours - (b.hours < 12) * b.hours
        || a.minutes - b.minutes;
});

console.log(array);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Sep 14, 2017 at 18:26

answered Sep 14, 2017 at 17:49

Nina Scholz

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Comments

Gershom Maes · Accepted Answer · 2017-09-14 17:48:39Z

You can use simple if statements in the Array.prototype.sort method to take multiple properties into account.

If two properties are exactly equal, consult the next most substantial property to break such ties.

var array = [
  { minutes: 45, hours: 4, meridiem: "PM" },
  { minutes: 00, hours: 8, meridiem: "AM" },
  { minutes: 45, hours: 8, meridiem: "AM" },
  { minutes: 30, hours: 3, meridiem: "PM" },
  { minutes: 15, hours: 11, meridiem: "AM" },
  { minutes: 00, hours: 1, meridiem: "PM" }
];

array.sort(function(a, b) {
  if (a.meridiem !== b.meridiem)
    return a.meridiem === 'AM' ? -1 : 1;
  
  if (a.hours !== b.hours)
    return a.hours - b.hours;
  
  return a.minutes - b.minutes
});

console.log(array);

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